Petroleum resins

ABSTRACT

In a process in which a C5 fraction from a cracked naphtha or gas oil is polymerized with the help of a Friedel Crafts catalyst to produce a petroleum resin, the resin properties are improved and polymerization time reduced by heating the C5 fraction to a temperature of at least 160*C for a period of up to 5 hours before the polymerization.

United States Patent [191 Hepworth et al.

[54] PETROLEUM RESINS [21] Appl. No.: 177,113

[30] Foreign Application Priority Data Sept. 7, 1970 Great Britain..42,768/70 [S2] U.S. Cl ..260/8 2, 260/33.6 PQ

[51] Int. Cl. ,.-....C08f 15/04, C08f 15/42 [58] Field of Search ..260/82 56] References Cited UNITED STATES PATENTS 2,734,046 2/1956 Nelsonetal ..260/82 [451 Jan. 9,1973

2,754,288 7/1956 2,894,937 7/1959 'Banes et al. 2,159,220 5/1939 McNultyet al.... 2,092,295 9/1937 van Peski et a]... 2,122,826 7/1938 van Peskiet al... 2,750,359 6/1956 Hamner et al ..260/82 Primary Examiner-HarryWong, Jr. Attorney-Cushman, Darby & Cushman 57 ABSTRACT In a process inwhich a C fraction from a cracked naphtha-or gas oil is polymerized withthe help of a Friedel Crafts catalyst to produce a petroleum resin,

the resin properties are improved and polymerization time reduced byheating the C fraction to a temperature of at least 160C for a period ofup to 5 hours before the polymerization.

7 Claims, No Drawings Banes et al. ..260/82 PETROLEUM RESINS Thisinvention relates to the production of petroleum resins.

The processing of crude petroleum gives rise to various hydrocarbonfractions which may subsequently be cracked" by heating, usually in thepresence of steam, to produce a range of lower boiling products amongwhich ethylene and propylene feature prominently. Naphtha (boiling range32 to 205C) and gas oil (boiling range 205 to 430C) are suitablecracking feedstocks. As well as ethylene and propylene the crackedproduct also contains hydrocarbons of increasing molecular weight andboiling point from butenes through pentenes, hexanes, naphthenes;aromatics to cyclic and acyclic hydrocarbons of even higher carbonnumber. It is customary to fractionate these hydrocarbons bydistillation into groups of compounds with similar boiling points. Thus,the C hydrocarbons removed as one fraction are followed by a range ofcompounds which may be designated for convenience as a C stream althoughcontaining residual C hydrocarbons and some lower boiling Chydrocarbons. It is this C stream, with or without further refining,which forms a suitable feedstock for the production of petroleum resins.

The resins, which vary in their properties as the hydrocarbon feedstockused in their preparation varies, are generally produced by treating thefeedstock with a polymerization catalyst such as aluminum chloride. Theunsaturated hydrocarbons in the feedstock undergo homoand crosspolymerization reactions which give rise to a resinous product. Forcommercial exploitation there are certain properties which are verydesirable in the finished resin, one of which is a ready solubility incommon hydrocarbon solvents such as white spirit and toluene. We havefound that this solubility of the resin is critically dependant on theratio of monoto conjugated diolefines in the polymerization feedstockand that by adjusting the mono-olefine to conjugated diolefine ratio asoluble resin may be produced. We have further found, however, that anunsuitable feedstock, i.e. a feedstock which would normally produce aninsoluble resin because its ratio of conjugated diolefines tomono-olefines is too high, may be converted into a suitable feedstock bya process of thermal treatment without the need for addition ofmono-olefines or conjugated diolefines.

According to the invention therefore a feedstock for petroleum resinmanufacture comprising a C stream distilled from a cracked naphtha orgas oil is preheated before conversion to the resin by heating to atemperature of at least I60C for a period of up to 5 hours. In generalthe higher the temperature the shorter the time, and vice versa.

The C stream is derived from a thermally or steam cracked naphtha or gasoil and typically boils in the range 10 to 80C. It generally containsmost of the following hydrocarbons, isoprene, cis and trans piperylene,n-pentane, isopentane, pentenel cyclopentadiene, dicyclopentadiene,trans-pentene-Z, 2-methylbutene-2, cyclopentene, cyclopentane andbenzene. If desired this C stream may be further refined before beingused in the process of the present invention, e.g. the isoprene may beremoved by distillation.

The C stream is heated to a temperature of at least C, preferably to atemperature in the'range l60 to 200C, particularly C, usually under itsautogeneous pressure. The time, required for the reaction to take placeis up to 5 hours and-is preferably 0.05 to 1.5 hours when thetemperature is about 170C.

When the C stream has been subjected to the pretreatment in accordancewith-thepresent invention it may be polymerized by means of a catalyst;to produce a resin. Thus Friedel Crafts catalysts are suitable e.g.inorganic halides and inorganic strong acids. Inorganic halides aregenerally preferred and includehalides of aluminum iron, tin, boron,zinc, antimony:and titanium which may be used in conjunction with ahydrogen halide such as hydrogen chloride. For example, treatment withaluminum chloride preferably complexed with hydrogen chloride in anaromatic solvent such as toluene or a xylene produces a solution fromwhich the resin may be recovered. Preferably, however, the FriedelCrafts catalyst is used in an aromatic solvent which is a benzene whichis liquid at the temperature of the polymerization and which issubstituted by at least one secondary or tertiary alkyl group or by acycloalkyl group, e.g. tert.butyl benzene, p-cymene, pisobutyl toluene,p-ethyl-tert.amyl benzene or, in particularly, cumene. Such catalystsare described in our co-pending British Pat. Application No. 5097/71 acomplex of aluminum chloride, cumene and hydrogen chloride beingpreferred. The polymerization of the C feedstock is preferably carriedout at a temperature of --l00 to +l00C under atmospheric pressure andthe catalyst is finally broken down and removed from the polymer bytreatment, for example with alcoholic ammonia or aqueous alkali followedby one or more washes with water and, optionally, a steam distillation,to removeresidual monomers. It is a further advantageous feature of theinvention that under comparable conditions the product of the presentprocess takes less time to polymerize than a starting material which hasnot undergone the pretreatment.

Although we do not wish to be bound by any theoretical speculation it isour opinion that the pretreatment of our novel process alters thecomposition of the C stream, probably by dimer formation notably amongthe conjugated diolefines. The resin is thus made up of the dimers crosspolymerized with other unsaturated components which are present, whereasin the untreated C stream the resin is formed mainly from the monomericcomponents. The process of our invention therefore as well as producingsoluble resins also produces a resin of novel structure in a reducedpolymerization time.

The heat treatment at a temperature of at least 160C and/or thepolymerization of the feedstock may be carried out batchwise orcontinuously, preferably the latter.

The invention will now be further described with reference to thefollowing Examples.

EXAMPLE a. A C stream from a steam cracked naphtha comprised isoprene,cis and trans-piperylene, n-pentane, isopentane, pentene-l,cyclopentadiene, dicyclopentadiene, trans-pentene-2, Z-methyl butene-2,cyclopentene, cyclopentane and benzene. This stream was heated for 6hours at 120C to convert the cyclopentadiene to dicyclopentadieneleaving the concentration of the monomer at less than [percent (if thecyclopentadiene remains as the monomer it tends to form a gelatinousprecipitate of polycyclopentadiene on subsequent polymerizing). Thisheat soaked material was then treated with an aluminum chloride/hydrogenchloride/toluene complex (equivalent to l to 2percent aluminum chloridebased on the quantity of C stream used) at ambient temperature for 4hours (the complex was added over a 3 hour period). The catalyst wasnext precipitated as aluminum hydroxide by adding ammaniacal methanol.The aluminum hydroxide was filtered off and the solution steam distilledto remove low molecular weight oils and unreacted dicyclopentadiene. Theresidue comprised the resin.

When the heat-soaked material contained a disproportionate amount ofconjugated diolefines to mono-olefines a resin was obtained which wasinsoluble in the usual hydrocarbon solvents such as white spirit andtoluene. This could be overcome by adding diisobutene, methyl styrene orisobutene as a source of mono-olefine to the feedstock before thepolymerization. Too much mono-olefine, however, resulted in a very softresin.

b. A C stream as defined in (a) above but which was deficient inmono-olefines and hence gave an insoluble resin was heated underautogeneous pressure at 170C for one hour. The product of thepretreatment was polymerized as above, the polymerization taking 2 hoursbut otherwise being identical with (a). The product was a resin solublein conventional aliphatic, cycloaliphatic and aromatic solvents andwhich compared with that produced in (a) as follows:

Yield 44% based on weight 40% based on weight ofc streamfeed ofCstreamfeed Sofiening Point C 99C Total time of reaction 10 hours 3 hoursI claim:

1. In a process for the production of a petroleum resin soluble inhydrocarbon solvents by polymerizing in the presence of a Friedel Craftscatalyst at C stream distilled from a cracked naptha or gas oil, theimprovement which comprises heating the C stream to a temperature in therange of at least C to about'200fC for a period of up to 5 hours beforecarrying out the polymerization 2. The process of claim 1 in whichisoprene present in the C stream is removed before the heating to atemperature of at least 160C.

3. The process of claim 1 in which the C stream is heated at C for 0.05to 1.5 hours.

4. The process of claim 1 in which the Friedel Crafts catalyst isaluminum chloride complexed with hydrogen chloride in an aromaticsolvent.

5. The process of claim 4 in which the aromatic solvent is toluene,xylene or a benzene which is substituted by at least one secondary ortertiary alkyl group or by cycloalkyl group.

6. A process of claim 1 in which the polymerizationis carried out at atemperature in the range l00 to 7. The process of claim 1 m WhlCh a Cstream boiling in the range 10 to 80C which has been distilled from astream cracked naphtha is heated at 170C for 0.05 to L5 hours and isthen polymerized by contact with an aluminum chloride and hydrogenchloride complex in toluene or cumene at a temperature in. the range l00to +l0OC to yield a petroleum resin which is recovered.

2. The process of claim 1 in which isoprene present in the C5 stream isremoved before the heating to a temperature of at least 160*C.
 3. Theprocess of claim 1 in which the C5 stream is heated at 170*C for 0.05 to1.5 hours.
 4. The process of claim 1 in which the Friedel Craftscatalyst is aluminum chloride complexed with hydrogen chloride in anaromatic solvent.
 5. The process of claim 4 in which the aromaticsolvent is toluene, xylene or a benzene which is substituted by at leastone secondary or tertiary alkyl group or by cycloalkyl group.
 6. Aprocess of claim 1 in which the polymerization is carried out at atemperature in the range -100* to +100*C.
 7. The process of claim 1 inwhich a C5 stream boiling in the range 10* to 80*C which has beendistilled from a stream cracked naphtha is heated at 170*C for 0.05 to1.5 hours and is then polymerized by contact with an aluminum chlorideand hydrogen chloride complex in toluene or cumene at a temperature inthe range -100* to +100*C to yield a petroleum resin which is recovered.